Smoking compositions containing a pyrazineethanol flavorant-release additive

ABSTRACT

This invention provides smoking compositions which contain a novel flavorant-release additive. 
     Under cigarette smoking conditions, a combustible filler and/or paper wrapper additive such as 2-(3-hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)--3,5,6-trimethylpyrazine releases pyrazine and cinnamaldehyde type of volatile flavorants into the cigarette smoke: ##STR1## A present invention flavorant-release additive is represented by the formula ##STR2## where R is hydrogen or methyl, R 1  is hydrogen or a C 1  -C 10  alkyl substituent; and R 2  is hydrogen or a C 1  -C 4  alkyl or C 1  -C 4  alkoxy substituent.

BACKGROUND OF THE INVENTION

It has been established that alkylpyrazines are natural components oftobacco smoke, and that they are contributors to tobacco smoke flavor[A. Baggett et al J. Chromatog. 97, 79 (1974)]. 2-Isopropenylpyrazinehas been identified as a tobacco flavorant constituent of burley tobacco[E. Demole et al, Helv. Chem. Acta, 55, 1866 (1972)].

Patents which disclose the addition of various pyrazine compounds totobacco and foodstuffs as a means of providing flavor or flavorenhancement include U.S. Pat. Nos. 3,684,809; 3,705,158; 3,754,934;3,764,349; 3,767,426; and 3,881,025.

It is characteristic of pyrazine and pyridine and other heteroaromaticderivatives employed as tobacco flavorants in the prior art that therespective derivatives have the disadvantage of both high volatility andlow odor threshold. Both of these properties significantly restrict theextent that these heteroaromatic derivatives can be utilized asflavorants in tobacco compositions. A quantity of a pyrazine or pyridinederivative in a tobacco composition sufficient to have a noticeableeffect in low delivery cigarettes causes a marked pack aroma.

U.S. Pat. No. 4,259,969 endeavors to overcome some of the disadvantagesof the above-described flavorant technology. The patent describessmoking composition flavorant-release additives which are not volatileat ambient temperatures, such as2-(2-hydroxy-2-phenylethyl)-3,5,6-trimethylpyrazine and relatedderivatives corresponding to the formula: ##STR3## wherein X is selectedfrom pyrazine and pyridine radicals corresponding to the chemicalstructures: ##STR4## where R is hydrogen or methyl; R¹ is hydrogen or C₁-C₁₀ alkyl; R² is a substituent selected from aliphatic, alicyclic andaromatic groups containing about 1-12 carbon atoms; and R¹ and R² whentaken together with connecting elements form an alicyclic structure.

Other smoking composition developments of interest with respect to thepresent invention are those in which an organic additive is utilizedthat releases at least two flavorants which are organolepticallycompatible, and enhance the flavor and aroma of cigarette smoke.

U.S. Pat. Nos. 4,036,237; 4,141,906; and 4,178,458 describeβ-hydroxyesters which as additives in smoking compositions pyrolyze intovolatile aldehyde and ester flavorants under smoking conditions.

U.S. Pat. Nos. 4,473,085 and 4,607,118 describe β-hydroxyesters which asadditives in smoking compositions pyrolyze into volatile ketone andester flavorants under smoking conditions.

U.S. Pat. No. 4,312,368 describes smoking compositions which contain aheterocyclic-hydroxy-substituted carboxylate flavorant-release additivesuch as ethyl 2-(2-butyl)-3-hydroxy-3-methyl-3--(3-pyridyl)propionate.Under smoking conditions this additive pyrolyzes into 3-acetylpyridineand ethyl β-methylvalerate flavorants.

There is continuing research effort to develop improved smokingcompositions which generate smoke with flavorant-enhanced taste andcharacter under smoking conditions.

Accordingly, it is an object of this invention to provide smokingcompositions having incorporated therein a flavorant component which ischaracterized by lack of mobility and/or volatility at ambienttemperature.

It is another object of this invention to provide smoking compositionshaving incorporated therein a flavorant-release additive which undernormal smoking conditions imparts improved flavor to mainstream smokeand improved aroma to sidestream smoke.

It is a further object of this invention to provide novel organiccompounds which are adapted to be incorporated into cigarette fillersand/or paper wrappers, and which under normal smoking conditions releasevolatile pyrazine and cinnamaldehyde type flavorant constituents intocigarette smoke.

Other objects and advantages of the present invention shall becomeapparent from the following description and examples.

DESCRIPTION OF THE INVENTION

One or more objects of the present invention are composition comprisingan admixture of (1) combustible filler selected from natural tobacco,reconstituted tobacco and tobacco substitutes, and (2) between about0.0001-5 weight percent, based on the total weight of filler, of aflavorant-release additive corresponding to the formula: ##STR5## whereR is hydrogen or methyl, R¹ is hydrogen or a C₁ -C₁₀ alkyl substituent;and R² is hydrogen or a C₁ -C₄ alkyl or C₁ -C₄ alkoxy substituent.

In another embodiment this invention provides a cigarette smokingproduct comprising (1) a combustible filler selected from naturaltobacco, reconstituted tobacco and tobacco substitutes, and (2) a paperwrapper which has incorporated therein a flavorant-release additivecorresponding to the formula: ##STR6## where R is hydrogen or methyl, R¹is hydrogen or a C₁ -C₁₀ alkyl substituent; and R² is hydrogen or a C₁-C₄ alkyl or C₁ -C₄ alkoxy substituent.

Illustrative of C₁ -C₄ alkyl and alkoxy substituents in the aboverepresented flavorant-release additive formula I are methyl, ethyl,propyl, 2propyl, butyl, 2-butyl and isobutyl groups, and thecorresponding alkoxy structures.

Illustrative of C₁ -C₁₀ alkyl substituents in formula I are the aboverecited C₁ -C₄ alkyl groups, and additionally structures such as pentyl,2-pentyl, hexyl, 2-hexyl, heptyl, octyl, isooctyl, nonyl and decylgroups.

A cigarette smoking product in accordance with the present inventiontypically contains between about 0.01-5 weight percent offlavorant-release additive in the paper wrapper, based on the weight ofcombustible filler.

In a further embodiment an invention cigarette product contains betweenabout 0.01-5 weight percent of flavorant-release additive in the paperwrapper, and contains between about 0.0001-5 weight percent offlavorant-release additive in the combustible filler.

A present invention flavorant-release additive in accordance withformula I which is incorporated in smoking compositions as describedabove is a low volatility compound which under normal smoking conditionspyrolyzes into volatile constituents which enhance the flavor and aromaof low delivery cigarette smoke: ##STR7## where R, R¹ and R² are aspreviously defined.

An important feature of an invention smoking composition having aformula I additive is the release of two flavorants under smokingconditions, one of which is a pyrazine and the other is a cinnamaldehydetype compound.

Both the pyrazine and cinnamaldehyde volatiles which are released havedesirable organoleptic properties. Each of the compounds contributes apleasant flavor and aroma to cigarette smoke. The pyrolysis of a presentinvention flavorant compound proceeds smoothly and quantitatively at atemperature as low as 175° C.

In another embodiment this invention provides a novel class ofpyrazineethanol compounds corresponding to the formula: ##STR8## where Ris hydrogen or methyl, R² is hydrogen or a C₁ -C₄ alkyl or C₁ -C₄ alkoxysubstituent; and R³ is a C₅ -C₁₀ alkyl substituent.

The formula II pyrazineethanol compounds exhibit unique properties whenutilized as a flavorant-release additive in a present invention smokingcomposition. In addition to imparting a pleasing flavor and aroma tocigarette smoke, a formula II flavorant-release additive tends to mellowthe harsh tone which is characteristic of sidestream smoke.

An important advantage of a present invention flavorant-release compoundis an excelIent stability property when utilized as a cigarette paperadditive and the paper is exposed to variable conditions of light andmoisture. Cigarette paper treated with a present inventionflavorant-release additive does not discolor under light and moistureexposure conditions due to decomposition of the additive.

PREPARATION OF FLAVORANT-RELEASE COMPOUNDS

A preferred method of preparing a formula I type of pyrazineethanolstructure is by the reaction of a methylpyrazine derivative with analdehyde derivative, both of which are appropriately substituted:##STR9##

The reaction is conducted in the presence of a strong base such asphenyllithium, lithium diisopropylamide or alkali metal hydride. Thestrong base initiates the in situ formation of a pyrazylmethylene anion.

Preferably, the base is added to the pyrazine starting material in aninert solvent medium maintained at a temperature between about 0° C. and50° C. and under an inert atmosphere. This procedure is followed by theaddition of the aldehyde compound to the reaction medium at atemperature between about -65° C. and 25° C. The resultanthydroxyethyl-substituted pyrazine product typically is an odorless,white crystalline solid.

PREPARATION OF SMOKING COMPOSITIONS

In a further embodiment, this invention provides a method of preparing asmoking composition which is adapted to impart flavor and aroma tomainstream and sidestream smoke under smoking conditions, which methodcomprises incorporating into natural tobacco, reconstituted tobacco ortobacco substitute between about 0.0001-5 weight percent, based oncomposition weight, of a flavorant-release additive corresponding toformula I as previously defined above.

The invention flavorant-release additive can be incorporated into thetobacco or tobacco substitute in accordance with methods known and usedin the art. Preferably the flavorant-release additive is dissolved in asolvent such as alcohol or aqueous alcohol and then sprayed or injectedinto the tobacco and/or tobacco substitute matrix. Such method ensuresan even distribution of the flavorant additive throughout the filler,and thereby facilitates the production of a more uniform smokingcomposition. Alternatively, the additive may be incorporated as part ofa concentrated tobacco extract which is applied to a fibrous tobacco webas in the manufacture of reconstituted tobacco. Another suitableprocedure is to incorporate the additive in tobacco or tobaccosubstitute filler in a concentration between about 0.5-5 weight percent,based on the weight of filler, and then subsequently to blend thetreated filler with filler which does not contain additive.

The term "tobacco substitute" is meant to include non-tobacco smokingfiller materials such as are disclosed in U.S. Pat. Nos. 3,703,177;3,796,222; 4,019,521; 4,079,742; and references cited therein;incorporated herein by reference.

As previously described hereinabove, an invention flavorant-releaseadditive also can be incorporated in the paper wrapper of cigaretteproducts, for the purpose of enhancing the aroma of cigarette sidestreamsmoke under smoking conditions. The incorporation can be accomplished bycoating the paper wrapper with a solvent solution of theflavorant-release additive, utilizing a size press or other conventionalcoating equipment. The flavorant-release additive also can beincorporated as a constituent of the composition used as a paper wrappersideseam adhesive.

The following Examples are further illustrative of the presentinvention. The specific ingredients and processing parameters arepresented as being typical, and various modifications can be derived inview of the foregoing disclosure within the scope of the invention.

EXAMPLE I2-(3-Hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine##STR10##

To a solution of lithium diisopropylamide (1.5 Molar, 73.3 mL, 0.11mole) in 150 mL of tetrahydrofuran at -78° C. is added slowly a solutionof tetramethylpyrazine (13.6 g, 0.1 mole) in 100 mL of tetrahydrofuran.The mixture is allowed to warm to room temperature and then cooled to-78° C. A solution of α-hexylcinnamaldehyde (23.7 g, 0.11 mole) in 100mL of tetrahydrofuran is added dropwise over 15 minutes. The solution isallowed to warm to room temperature, and then poured into an ice/dilutehydrochloric acid mixture. The organic layer is separated and washedwith saturated solutions of sodium bicarbonate and sodium chloride. Thesolution is dried over anhydrous magnesium sulfate. After filtration ofdrying agent and evaporation of solvent, a yield of 40 g of crudematerial is obtained. A volatile fraction in the crude material isremoved by distillation at below 85° C. under 0.15 torr of mercury. Theresidue is crystallized from a mixture of ethyl acetate-hexane. Theproduct is obtained as a fine needle, M.P. 61°-62° C. Yield 26 g (70%).NMR and IR confirm the structure.

Anal. Calc. for C₂₃ H₃₂ N₂ O: C,78.37;H, 9.15;N, 7.95.

Found: C,78.37;H,9.14;N,7.83.

EXAMPLE II 2-(2-Hydroxy-4-phenyl-3-buten-1-yl)-3 5.6-trimethylpyrazine##STR11##

To a solution of lithium diisopropylamide (1.5 Molar, 73.3 mL, 0.11mole) in 150 mL of tetrahydrofuran at -78° C. is added slowly a solutionof tetramethylpyrazine (13.6 g, 0.1 mole) in 100 mL of tetrahydrofuran.The mixture is allowed to warm to room temperature and then cooled to-78° C. A solution of cinnamaldehyde (14.5 g, 0.11 mole) in 100 mL oftetrahydrofuran is added dropwise over 15 minutes. The reaction productmixture is then worked up according to the procedures of Example I toprovide the title compound.

EXAMPLE III 2-(3-Hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)-3-methylpyrazine##STR12##

To a solution of lithium diisopropylamide (1.5 Molar, 73.3 mL, 0.11mole) in 150 mL of tetrahydrofuran at -78° C. is added slowly to asolution of 2,3-dimethylpyrazine (10.8 g, 0.1 mole) in 100 mL oftetrahydrofuran. The mixture is allowed to warm to room temperature andthen cooled to -78° C. A solution of α-hexylcinnamaldehyde (23.7 g, 0.11mole) in 100 mL of tetrahydrofuran is added dropwise over 15 minutes.The reaction product mixture is then worked up according to theprocedures of Example I to provide the title compound.

EXAMPLE IV 2-(2-Hydroxy-4-phenyl-3-buten-1-yl)-6-methylpvrazine##STR13##

To a solution of lithium diisopropylamide (1.5 Molar, 73.3 mL, 0.11mole) in 150 mL of tetrahydrofuran at -78° C. is added slowly a solutionof 2,6-dimethylpyrazine (10.8 g, 0.1 mole) in 100 mL of tetrahydrofuran.The mixture is allowed to warm to room temperature and then cooled to-78° C. A solution of cinnamaldehyde (14.5 g, 0.11 mole) in 100 mL oftetrahydrofuran is added dropwise over 15 minutes. The reaction productmixture is then worked up according to the procedures of Example I toprovide the title compound.

EXAMPLE V2-(2-Hydroxy-4-p-methoxyphenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine##STR14##

To a solution of lithium diisopropylamide (1.5 Molar, 73.3 mL, 0.11mole) in 150 mL of tetrahydrofuran at -78° C. is added slowly a solutionof tetramethylpyrazine (13.6 g, 0.1 mole) in 100 mL of tetrahydrofuran.The mixture is allowed to warm to room temperature and then cooled to-78° C. A solution of p-methoxycinnamaldehyde (17.8 g, 0.11 mole) in 100mL of tetrahydrofuran is added dropwise over 15 minutes. The reactionproduct mixture is then worked up according to the procedures of ExampleI to provide the title compound.

EXAMPLE VI 2-(2-Hydroxy-4-p-methoxyphenyl-3-buten-1-yl)pyrazine##STR15##

To a solution of lithium diisopropylamide (1.5 Molar, 73.3 mL, 0.11mole) in 150 mL of tetrahydrofuran at -78° C. is added slowly to asolution of 2-methylpyrazine (9.4 g, 0.1 mole) in 100 mL oftetrahydrofuran. The mixture is allowed to warm to room temperature andthen cooled to -78° C. A solution of p-methoxycinnamaldehyde (17.8 g,0.11 mole) in 100 mL of tetrahydrofuran is added dropwise over 15minutes. The reaction product mixture is then worked up according to theprocedure of Example I to provide the title compound.

EXAMPLE VII

A 2% solution of the Example I compound in 95% ethanol is applied to thepaper wrapper of cigarettes to obtain about 0.5 mg of the compound percigarette. The cigarettes are smoked and evaluated by an experiencedsmoking panel in comparison to untreated control cigarettes. The treatedcigarettes exhibit pleasant herbal-spicy aromas in the sidestream smokewithout a significant change in the taste of the cigarettes (mainstreamsmoke).

What is claimed is:
 1. A smoking composition comprising an admixture of(1) combustible filler selected from natural tobacco, reconstitutedtobacco and tobacco substitutes, and (2) between about 0.0001-5 weightpercent, based on the total weight of filler, of a flavorant-releaseadditive corresponding to the formula: ##STR16## where R is hydrogen ormethyl, R¹ is hydrogen or a C₁ -C₁₀ alkyl substituent; and R² ishydrogen or a C₁ -C₄ alkyl or C₁ -C₄ alkoxy substituent.
 2. A smokingcomposition in accordance with claim 1 wherein the flavorant-releaseadditive is2-(3-hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine. 3.A smoking composition in accordance with claim 1 wherein theflavorant-release additive is2-(2-hydroxy-4-phenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine.
 4. Asmoking composition in accordance with claim 1 wherein theflavorant-release additive is2-(3-hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)-3--methylpyrazine.
 5. Asmoking composition in accordance with claim 1 wherein theflavorant-release additive is2-(2-hydroxy-4-phenyl-3-buten-1-yl)-6-methylpyrazine.
 6. A smokingcomposition in accordance with claim 1 wherein the flavorant-releaseadditive is2-(2-hydroxy-4-p-methoxyphenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine. 7.A smoking composition in accordance with claim 1 wherein theflavorant-release additive is2-(2-hydroxy-4-p-methoxyphenyl-3-buten-1-yl)-pyrazine.
 8. A cigarettesmoking product comprising (1) a combustible filler selected fromnatural tobacco, reconstituted tobacco and tobacco substitutes, and (2)a paper wrapper which has incorporated therein a flavorant-releaseadditive corresponding to the formula: ##STR17## where R is hydrogen ormethyl, R¹ is hydrogen or a C₁ -C₁₀ alkyl substituent; and R² ishydrogen or a C₁ -C₄ alkyl or C₁ -C₄ alkoxy substituent.
 9. A cigarettesmoking product in accordance with claim 8 wherein the paper wrappercontains between about 0.01-5 weight percent of flavorant-releaseadditive.
 10. A cigarette smoking product in accordance with claim 8wherein the flavorant-release additive in the paper wrapper is2-(3-hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine. 11.A cigarette smoking product in accordance with claim 8 wherein theflavorant-release additive in the paper wrapper is2-(2-hydroxy-4-phenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine.
 12. Acigarette smoking product in accordance with claim 8 wherein theflavorant-release additive in the paper wrapper is2-(3-hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)-3-methylpyrazine.
 13. Acigarette smoking product in accordance with claim 8 wherein theflavorant-release additive in the paper wrapper is2-(2-hydroxy-4-phenyl-3-buten-1-yl)-6-methylpyrazine.
 14. A cigarettesmoking product in accordance with claim 8 wherein the flavorant-releaseadditive in the paper wrapper is2-(2-hydroxy-4-p-methoxyphenyl-3-buten-1-yl) -3,5,6-trimethylpyrazine.15. A cigarette smoking composition in accordance with claim 8 whereinthe flavorant-release additive in the paper wrapper is2-(2-hydroxy-4-p-methoxyphenyl-3-buten-1-yl) -pyrazine.
 16. A cigarettesmoking product in accordance with claim 8 wherein the combustiblefiller contains between about 0.0001-15 weight percent, based on theweight of filler, of a flavorant-release additive corresponding to theformula: ##STR18## where R is hydrogen or methyl, R¹ is hydrogen or a C₁-C₁₀ alkyl substituent; and R² is hydrogen or a C₁ -C₄ alkyl or C₁ -C₄alkoxy substituent.
 17. A cigarette smoking product in accordance withclaim 16 wherein the flavorant-release additive in the combustiblefiller is2-(3-hexyl-2-hydroxy-4-phenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine. 18.A cigarette smoking product in accordance with claim 16 wherein theflavorant-release additive in the combustible filler is2-(2-hydroxy-4-phenyl-3-buten-1-yl) -3,5,6-trimethylpyrazine.
 19. Acigarette smoking product in accordance with claim 16 wherein theflavorant-release additive in the combustible filler is2-(3-hexyl-2-hydroxy-4-phenyl-3-buten -1-yl)-3-methylpyrazine.
 20. Acigarette smoking product in accordance with claim 16 wherein theflavorant-release additive in the combustible filler is2-(2-hydroxy-4-phenyl-3-buten-1-yl)-6-methylpyrazine.
 21. A cigarettesmoking product in accordance with claim 16 wherein theflavorant-release additive in the combustible filler is2-(2-hydroxy-4-p-methoxyphenyl-3-buten-1-yl)-3,5,6-trimethylpyrazine.22. A cigarette smoking product in accordance with claim 16 wherein theflavorant-release additive in the combustible filler is2-(2-hydroxy-4-p-methoxyphenyl-3-buten-1-yl)-pyrazine.